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[Bug tree-optimization/83126] [8 Regression] ICE in transform_to_exit_first_loop_alt, at tree-parloops.c:1713
- From: "vries at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 12 Feb 2018 15:01:04 +0000
- Subject: [Bug tree-optimization/83126] [8 Regression] ICE in transform_to_exit_first_loop_alt, at tree-parloops.c:1713
- Auto-submitted: auto-generated
- References: <bug-83126-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83126
--- Comment #4 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #3)
> This is the usual "you should not repeat analysis during transform" issue.
> The vectorizer gets around this by caching relevant scalar evolution
> but obviously that's difficult if using generic stuff like
> canonicalize_loop_ivs ...
I wonder if it makes sense to add an interface to scalar_evolution_info to
update the instantiated_below field for existing entries. So, before the loop
versioning, the loop preheader is bb10, but after loop versioning, it's bb15.
If we update the instantiated_below field from 10 to 15, the cached scalar
evolution info can still be used.